Early verdictsA September 2025 report by planning consultancy Marrons shows developers are using greybelt rules to successfully appeal rejected proposals. Loading…Recent judgements suggest planning inspectors are not treating greybelt as a catch-all excuse to build anywhere in the greenbelt. Previously, greenbelt areas often delayed the updating of local plans to avoid having to allocate greenbelt sites for development. “The greenbelt is probably the most popular planning policy there has ever been.” As he puts it: “One of the silver linings behind the greybelt concept is that it’s ultimately about the contribution of greenbelt land and its performance.”